The present invention relates to apparatus for removing trim which is severed from a web of material, such as paper, as the web is passed between an anvil roller and a cutting roller in a rotary cutter. More particularly, the invention relates to moving a set of pins into position to impale the trim or scrap on the pins as it is cut from the web, and then moving the pins with scrap impaled thereon past an abutment which lifts the scrap from the pins. In a preferred form of the invention the abutment is a belt moving alongside and away from the pins as the pins pass the belt, thus combining the lifting engagement of the moving belt on the scrap with the movement of the pins past and away from the belt. A nip roller may be associated with the belt by being moveable onto it to seize the leading edge of the scrap between the belt and the roller as the pins are withdrawn from the scrap. In another form of the invention the abutment may be a comb through which the pins, initially with scrap impaled upon them, are passed, and having an adjacent, cooperative nip roller moveable onto or engaged upon the comb to seize the scrap between the roller and the comb as the pins are withdrawn from the scrap.
Heretofore, in apparatus for stripping scrap from a web which has been severed into sheets, or from a portion of a web which has been trimmed such as in cutting it to form envelope windows, the scrap pieces have been impaled upon pins to pull the scrap out of the path of the trimmed products formed from the web. Once the scrap pieces are impaled, the pins are moved arcuately to pass them through a comb. There, as the pins are moved through and past the teeth of the comb, the pieces of scrap are scraped off the pins, thence to fall from the comb and be removed, such as by letting them fall into a hopper which is removed as it becomes filled, or by vacuuming the pieces of scrap away.
Such is the arrangement of U.S. Pat. No. 3,893,359 to Gregoire, for example. A series of radially extending impalement pins are arranged along a stripping roller in a rotary cutter. The rotary cutter includes an anvil roller against which radially extending longitudinally arranged parallel knife blades on the cutting roller are brought to bear as a moving web is passed between the anvil and cutting rollers. Adjacent the stripping roller a comb is mounted in a position to require the pins to pass through its teeth. In operation, the knife blades sever a piece of scrap from the web, and the severed piece remains between the blades momentarily. However, as the cutting roller continues to rotate the severed piece of scrap between the blades is brought opposite the set of impalement pins. The pins are rotated into penetration of the scrap, and, thus impaled, the scrap is drawn from between the knife blades and carried away on the stripping roller. Thereafter, the severed piece of scrap is carried by the pins around the stripping roller to a point where the pins pass through the teeth of the comb. Thus the pins are withdrawn from the scrap as the stripper roller continues to rotate past the comb.
A generally similar form of scrap stripping apparatus is shown and described in a U.S. Pat. to McMahon et al., U.S. Pat. No. 4,640,165 issued Feb. 3, 1987. In that application, the comb is illustrated as being somewhat curved about the cutting roller near the extremities of its teeth.
Other patents which may be of interest in this field are the following U.S. Pat. Nos. 3,270,602 to K. Kirby et al., 3,186,274 to R. Winkler et al., and 2,381,955 to L. Hoffman et al. In the last-mentioned patent, a pivotally mounted doctor blade is urged by a spring against a roller carrying a set of picker pins. The base of the doctor blade is supported in a bracket which can be adjusted pivotally to dispose the blade toward or away from the roller carrying the picker pins, and the base of the doctor blade can also be moved longitudinally along the roller so that the teeth of the doctor blade can properly intercept the pins.
In these and other arrangements of the prior art the blades or combs have had to be adjusted so that their teeth intercept the scrap with the points of the teeth between the pieces of scrap and the body of the stripper roller. As the cutters are used, the press operators must keep a watchful eye upon their stripping operations to be sure that the stripping teeth continue to function and do not block or pile up scrap. Vibrations within the equipment as the cutters are run at high speeds can sometimes cause the stripping teeth to get out of adjustment. And also, when the cutters are run at high speeds, the rapid movement of the scrap pieces onto the stripping teeth may sometimes cause the scrap to tear or otherwise be incompletely removed because portions stick on the impaling pins.
This invention also eliminates the need for pins in the cutting anvil which greatly improves anvil life and flexibility especially when cutting complex die cut shapes.